'The man on the rock hugged his radio as if it were a child. It was the only thing he took when he left his village' Photograph: Jim Goldberg

I took this picture last year, before Christmas, in a refugee camp in the Democratic Republic of Congo. I was finishing up a six-year project on immigrants, refugees and trafficked people. This man is sitting on a rock overlooking the camp. To his right you can see around 50 huts; if you looked in the direction he is looking, you would see the other 90,000 people living there.

A few minutes after I took this, he came over and talked to me about his life. He hugged his radio as if it were a child – it was the only thing he took when he left his village. These are people who have been caught in the crossfire of civil war for 18 years.

Isolating one picture from this shoot was difficult: I think of them more as jigsaw pieces. But I like this one because I see so much of what the people in the picture have to contend with. It's a beautiful expanse, with wonderful clouds, the hill in the distance, houses and crops – but these people have no access to that; they're basically stuck in the camp. Just out of sight, on the left, that's where the rebels are. A week or two later, they moved all 90,000 people, and this place no longer exists.

One thing you may not see is the amazing light: it was filtered through the grey clouds, streaming in as if God were sending down shafts to illuminate the landscape. I was watching that big storm cloud in the middle because I couldn't move quickly – I was shooting on a big 4x5 camera. In fact, I had a whole bunch of cameras: Polaroids, video, point-and-shoot, medium format and 35mm.

I began this project in 2003, when I was asked to photograph immigrants in Greece, part of a commission to document different aspects of the country in the run-up to the 2004 Olympics. I realised very quickly that immigration is a complex affair: some were economic migrants, others were refugees looking for asylum, others had been forced there by traffickers and sold into prostitution. It all added up to something much deeper than saying: 'These are immigrants.' It took me six years to deal with that complexity.

Born: Newhaven, Connecticut, 1953

Studied: MFA in photography, San Francisco Institute

Inspiration: "The old guys, of course: Walker Evans, Eugène Atget, Timothy O'Sullivan. But also Christian Boltanski, Robert Rauschenberg. They teach me how to loosen up my work."

Top tip: "I use my intuition. I tell my students: use your brains, but also use another part of yourself."